Novel photographic elements protected against ultraviolet radiation



y 31, 1966 G. w. SAWDEY 3,253,921

NOVEL PHOTOGRAPHIC ELEMENTS PROTECTED AGAINST ULTRAVIOLET RADIATION Filed Oct. 10, 1961 GELAT/IV OVERCOAT RED SENS/Tl l/E EMULSION C0/V7I4l/Vl/V6 CYA/V DYE FORMER GEL 47w CO/VTA/IV/IVG 2- (2 wrmoxr-s $000711 PHE/VYL) smzommzom 6' RE E /V $E/V$/ 77 l/E EMULSION CONTA/IV/IVG MAGE/WZJ DYE FORMER BLUE -$E N57 7' VE EMULSION CO/VM/Nl/VG YELLOW DYE FORMER PA PER SUPPORT GEORGE W SAWDE Y INVENTOR. R. 3'. Y

ATTORNEY 8 AGE/VT United States Patent 3,253,921 NOVEL PHOTOGRAPHIC ELEMENTS PROTECTED AGAINST ULTRAVIOLET RADIATION George W. Sawdey, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Oct. 10, 1961, Ser. No. 144,228 19 Claims. (Cl. 96-73) This invention relates to the incorporation of ultraviolet absorbers in photographic products and particularly to the incorporation of ultraviolet absorbers in color photographic elements to protect dye images against the harmful effects of ultraviolet radiation.

It is known that ultraviolet radiation has a detrimental effect on photographic layers. Ultraviolet radiation in light sources used for exposure of photographic products sometimes produces undesired exposure of the layer or layers of a photographic element. This is especially true in photographic elements designed for use in color photography in which the emulsion has been sensitized to the longer wavelength regions and it is desirable to record only the rays of the visible spectrum.

Color photographs on multilayer photographic material, particularly those in which the dye images are formed in sensitive emulsion layers by color development, are susceptible to fading and discoloration by the action of ultraviolet radiation to which the photographs are subjected during viewing. The residual couplers contained in the emulsion layer (in certain processes) after the formation of the picture images are attacked by ultraviolet radiation resulting in an undesirable stain in the finished photograph. The action of ultraviolet radiation on finished color photographs is particularly noticeable on positive prints on paper or other opaque support since this type of print is frequently viewed in daylight which has a high content of ultraviolet radiation. The dye-fading and discoloration elfects appear to be caused primarily by those Wavelengths of light close to the visual region of the spectrum, i.e., 300-400 III/1..

It is known that silver halide photographic materials can be protected from ultraviolet radiation by incorporating nondifiusing ultraviolet absorbing compounds in the silver halide emulsion layers or in overlying colloid coatmgs.

A large number of ultraviolet absorbers have been proposed for this use. Ultraviolet absorbing compounds for photographic use must generally be colorless or nearly colorless, show good compatability with the medium in which they are incorporated, be inert to other photographic addenda in the element and in the processing solution, must have good ultraviolet absorptivity and be stable to ultraviolet radiation. Representative compounds for incorporation in photographic elements are described, for example, in U.S. Patent 2,685,512, issued August 3, 1954; U.S. Patent 2,739,888, issued March 27, 1956; U.S. Patent 2,719,086, issued September 27, 1955; U.S. Patent 2,739,971, issued March 27, 1956; U.S. Patent 2,747,- 996, issued May 29, 1956, and U.S. Patent 2,784,087, issued March 5, 1957.

Ordinarily, aromatic organic compounds like ultraviolet absorbers, dye-forming couplers, antistain agents, filter dyes, etc., have been made nondiffusing by addition of hydrophobic ballasting groups and require special techniques for incorporating them in a sufliciently high-dispersed form in aqueous photographic gelatin layers.

A typical procedure for accomplishing finely-divided particulate dispersions and avoiding unwanted crystallization or other aggregation of particles is the so-called Fischer method in which a nondiflusing compound is provided with a sulfonic acid or other solubilizing group so that it can be dissolved in water as the alkali metal salt Patented May 31, 1966 and the solution added to the aqueous gelatin coating composition.

This Fischer technique as applied to dye-formingcouplers is described, for example, in U.S. Patent 2,186,849, issued January 9, 1940.

Ultraviolet absorbing compounds suitable for addition to photographic emulsions and containing sulfonic or carboxylic acid functions to facilitate incorporation into photographic gelatin layers by the Fischer procedure are described in U.S. Patents, 2,685,512, issued August 3, 1954; 2,719,086, issued September 27, 1955; 2,739,888, issued March 27, 1956; 2,747,996, issued May 29, 1956; 2,784,087, issued March 5, 1957; 2,798,067, issued July 2, 1957; 2,808,330, issued October 1, 1957; and 2,875,053, issued February 24, 1959. British Patents 761,728, issued November 21, 1956; and 783,325, issued September 18, 1957; Belgian Patent 527,404, granted September 18, 1954, and German Patent 950,890, issued October 18, 1956.

The Fischer method is convenient for incorporating ultraviolet absorbers in finely-divided and uniformly dispersed form and the resulting ultraviolet absorbing layers have shown good long-term stability.

Another technique employed in incorporating ultraviolet absorbing compounds into gelatin layers is by dissolving the absorber in a polar solvent, e.g., water and/or methanol, and then bathing the photographic gelatin coating in this solution. A typical example of this method is disclosed in U.S. Patents 2,685,512; 2,719,086; 2,747, 996; and 2,808,330. This imbibition method is advantageous for the incorporation of ultraviolet absorbers into processed photographic strips for the purpose of protecting the images from the harmful effects of ultraviolet radiation.

Another typical method for incorporating compounds in finely-divided, noncrystallized form is the solvent-dispersion technique in which the nonditfusing compound is dissolved in an organic solvent and the resulting solution is intimately blended in an aqueous gelatin solution. This technique as applied to couplers is described, for example, in U.S. Patents 2,322,027, issued June 15, 1943; 2,801,170 and 2,801,171, both issued July 30, 1957; 2,- 870,012, issued January 20, 1959, and 2,991,177, issued July 4, 1961.

A typical example of the use of the solvent dispersion technique as applied to ultraviolet absorbers is described in U.S. Patent 2,739,888, issued March 27, 1961.

This solvent dispersion technique has important technological advantages for introducing nondifiusing aromatic compounds into aqueous gelatin coating compositions. However, the stability to light of ultraviolet absorbing compounds incorporated by this method is generally poorer than that of those incorporated by the Fischer method.

The poor stability of these compounds when dispersed by the solvent dispersion method may be due to the presence of organic solvent with the compound in the protective colloid.

I have found certain hydrophobic nondiffusing hydroxyphenylbenzotriazole compounds which are extremely useful as ultraviolet absorbers in photographic gelatin layers. Compounds of this class exhibit desirable absorption characteristics in the ultraviolet region, i.e., maximum absorption in the near ultraviolet and sharp cut-off just outside the visible region, are colorless, are readily dispersed by either the solvent-dispersion or imbibition methods, and are photographically inert.

However, when these compounds are incorporated into photographic gelatin layers by the imbibition method or using the Fischer analog of these compounds containing a water-solubilizing group, to incorporate them by the t W T 3 Fischer method, the stability to light of the gelatin coating containing the ultraviolet compound is poor.

Surprisingly, when compounds of this class are incorporated by the solvent dispersion technique, the stability 4 The compounds of Formula I are incorporated in solvent dispersion advantageously by dissolving them in either a high boiling water-immiscible organic solvent, 21 low boiling organic solvent, or a water-soluble organic to light is excellent. 5 solvent, or in a mixture of a high boiling water-im- The related nonhydroxylated phenylbenzotriazoles do miscible organic solvent and/or a low boiling and/or not exhibit this stability advantage when incorporated b Water-soluble organic solvent. the solvent dispersion technique. Any of the high boiling Water-immiscible solvents The stability of my hydrophobic nondiffusing hydroxydescribed in U.S. Patent 2,322,027, issued June 15, 1943, phenylbenzotriazole ultraviolet absorbers incorported by may be used as solvents. The preferred solvents include the solvent dispersion technique is the result of the con1- di-n-butylphthalate, benzylphthalate, triphenyl phosphate, bination of this class of nondiffusing hydroxybenzotri tri-o-cresyl phosphate, diphenyl mono-p-tert-butyl phenyl azoles with the specific method of dispersing them. phosphate, monophenyl di-p-tert-butyl phenyl phosphate, An object of my invention is to provide novel photodiphenyl mono-o-chlorophenyl phosphate, monophenyl graphic elements protected against the harmful effects of di-o-chlorophenyl phosphate, tri-p-tert-butylphenyl phosultraviolet radiation by incorporation of ultraviolet abphate, tri-o-phenylphenyl phosphate, di-p-tert-butylphenyl sorbing materials. Another object is to provide photomono(5-tert-butyl-2-phenylpheny1)phosphate, etc. graphic color materials containing ultraviolet absorbers The low boiling or water-soluble organic solvents incorporated in a highly stable form. A further object which can be used to advantage with or in place of a is to provide a nondiffusing ultraviolet absorber. Other high boiling solvent are disclosed in patents, such as objects will become apparent from a consideration of Fierke et al., U.S. 2,801,171, and Vitturn et al., U.S. the following specification and claims. 2,801,170, both issued July 30, 1957; Julian, U.S. 2,949,-

According to my invention, these and other objects are 360, issued August 16, 1960; etc. The organic solvents accomplished by the use of the solvent dispersion techniinclude: que to incorporate in aqueous hydrophilic colloid solu- (1) Low boiling substantially water-insoluble organic tions for coating silver halide emulsion layers or assosolvents, such as methyl, ethyl, propyl and butyl acetates, ciated hydrophilic colloid layers, an ultraviolet-radiationisopropyl acetate, ethyl propionate, sec-butyl alcohol, absorbing compound represented by the following forethyl formate, butyl formate, nitromethane, nitroethane, mula: carbon tetrachloride, chloroform, etc., and (I) N OH (2) Water-soluble organic solvents, such as methyl l isobutyl ketone, fl-ethoxy ethyl acetate, fi-butoxy p-ethoxy R N@ ethyl acetate, tetrahydrofurfuryl adipate, Carbitol acetate R2 (diethylene glycol monoacetate), methoxy triglycol ace- N tate, methyl Cellosolve acetate, acetonyl acetone, diacetone wherein R, R1 and R2 can each represent a hydrogen alcohol, butyl Carbitol, butyl Cellosolve, methyl carbitol, atom, a halogen atom, such as chlorine, bromine, iodine, methyl CeHOSOlVe, e hylene glycol, diethylene glycol, dietc., a nitro group, an alkyl group having from 1 to 18 propylene glycol, acetone, methanol, ethanol, acetonitrile, carbon atoms such as methyl, ethyl, propyl, isopropyl, dlmethylformamme: 1 9 aminopropyl, butyl, sec-butyl, chlorobutyl, amyl, iso Any water present in the solvent solution must be low hexyl, octyl, nonyl, steal-amidobutyl, decyl, dodecyl, enough not to affect adversely the solubility of the tadecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, phenylabsorberethyl, phenylpmpyl etc., an alkoxy group having f The methods for remov ng the low boiling or water- 1 to 18 carbon atoms, Such as methoxy, propoxy, ch1or0 soluble solvents from the dispersion, for example, by airbutoxy, decoxy, nonoxy, diamylphenoxyethoxy, Pentadrying a chilled, noodled dispersion or by continuous decoxy, octadecoxy carbomethoxy carbobutoxy cap Water-wash ng are described in, for example, U.S. Patent bohexoxy, carbododecoxy, carbopentadecoxy, etc., an 28O111711sSPed July 1957- aryl group, such as phenyl, 4 methy1pheny1 4 ethoxy Thefollowing representative compounds of Formula I phenyl, 2 heXOXypheny1, g h h l etc an aryloxy listed in Table I vvill serve to illustrate the compounds group such as phenoxy, 4 methylphenoxy, z propylphen useful in my ultraviolet absorbing layers but are not conoxy, 3-amylphenoxy, etc., such that at least one of the sldered as llmlting 1116 inventiongroups, R, R and R shall contain at least 5 carbon N on R 1 atoms, and the total number of carbon atoms represented 4 3\ in R +R is at least 8. 2N

The compounds defined by Formula I are nondiflusing 6 u and have the solubility characteristics needed to carry out my invention advantageously.

TABLE I Compound Benzotriazole R R1 R2 Number 2-(2-hydroxy-5-isooctylphcnyl) H H CsHn-i 2-(2-hydroxy-5-n-octylphenyl) H H C H -n 2-(Zfigfigoxyi,5-di-tertamyl- H C5Hn-t C5H11-t 2-FZ-hydroxy-5-d0decylphenyl) H II C12H25-Il 2-(2-hydroxy-5'-hexadecylphenyl) H H CwHaa-n 2-gfigigggoxy-3-tert-an1yl-5'-benzyl- H C5H11-t CIgIz o' 2-ggg giioxy-y-tert-amyl-5-phenyl- H 051111-13 0511 5 5methyl-2-(2-l1ydroxy-5-iso0ctyl- CH3 H CEHlT-i phenyl) 50ctyl-2-(2-hydr0xy-5-is0octyl- C HU-n H CsHn-i phenyl) A dcarbobutoxy-Z-(2-l1ydroxy-3-n- C4H9OOC CgI'Ig-Il CsIIn-t butyl-5-tert-arnylplicnyl) 5-chloro-2-(2-liydroxy-3-n-amyl-5- Cl C Hun C6115 phcnylphenyl) 5-meth0xy-2-(2-hy(lroxy-3-5-di CI'IQO O IIn-t C Hn-t tert-amylphenyl) TABLE I-Continued Aqueous alcohol solution of the ultraviolet absorbing compounds of my invention were imbibed into gelatin layers. For example, a 9:1 methanol-water solution was made of each of my ultraviolet absorber compounds 1, 2, and 3, and the resulting solutions were imbibed into elatin layers by immersing the gelatin coating into the ultraviolet absorber solution. These coatings were subsequently dried, and Cary spectrophotometer traces were made for each of these coatings before and after 85 hours exposure to a xenon arc. The exposure resulted in considerable loss in the usefulness of these layers for photographic materials.

I have now found that the ultraviolet absorbing compounds of Formula I incorporated in photographic gelatin layers according to the method used in my invention have unexpectedly high stability to prolonged exposure to ultraviolet radiation.

The advantage in the improved stability of ultraviolet absorbing coatings made according to my invention using the solvent dispersion technique is illustrative by the following example. Examp 1e 1 Seven ultraviolet absorbing compounds of my invention (Formula I), a related nonhydroxylated compound, and a Fischer analog were coated in gelatin layers. Coatings 1, 3, 6 and 8 were made from the following composition:

Ultraviolet absorber g 0.5 Tri-o-cresyl phosphate -ml 0.25 Ethyl acetate ml 3.0 gelatin solution ml 22.0 5% Alkanol B solution ml 2.0

(propylated naphthalene sulfonate) 2.81 g. for an hour in a solution containing 10 ml. of 6 percent gelatin, 1.5 ml. of 7.5 percent saponin and 30 ml. of water. Three milliliters of this dispersion was coated on clear film support to a wet thickness of 0.003 ultraviolet absorber, 25 mg./ft. of solvent, and 200 mg./ ft? of gelatin.

Coatings 2, 4 and 7 were made by the same procedure excepting that the amount of absorber used was increased in the coating composition so that the coatings contained 100 mg./ft. of the absorber instead of mg./ft.

Coating 5 was made by a procedure similar to that used for Coating 1 but the coating composition contained no tri-o-cresyl phosphate. The amount of absorber was increased so it would coat at mg./ft.

Coating 9 was made from the dispersion described below. A dispersion was made by dissolving 1.0 g. of 2-(2-hydroxy-5-iso-octyl x sulfophenyl)benzotriazole, sodium salt in a solution containing 22 ml. of 10 percent gelatin, 2 ml. of 5 percent propylated naphthylene sulfonate, 2 ml. of 7.5 percent saponin and 14 ml. of water. This mixture was coated on a clear film support to a wet thickness of 0.003 of an inch. The coating contained 100 mg./ft. of ultraviolet absorber and 200 mg./ft. of gelatin.

Cary spectrophotometer traces were made of finished Coatings 1 through 9 to show the spectral absorption at wavelengths from 250 to 500 m The coatings were exposed to a xenon are for the times indicated in the table, then new traces were made and the percent loss in absorption determined at the arbitrarily chosen A370 m t. These values are summarized in Table II.

The advantage in the improved stability of the compounds of Formula I when incorporated by the solvent dispersion technique is contrasted with the comparatively poor stability of corresponding samples coated by the other two procedures, i.e., molecular solutions or by Fischer-type solutions, was quite unexpected. This stability is shown in the following Table II comparing the solvent dispersion technique and the Fischer technique for compounds of Formula I and analogous structures.

TABLE II Percent Loss in Transmission Ratio of Coating Density of Xenon Are Coating Ultraviolet Absorber Absorber to Rate in Coating at Exp. Time Solvent trig/ 15. A370 m in Hours Caused by Exposure to Xenon Arc 2-(2-hydr0xy-5-is0octylphenyl) 1:% 50 2. 1 100 benzotrinzole. 2- (2-hydroxy-5-isooctylpheny1) 1:% 100 0 100 benzotriazole. 2-(2hydroxy-3,5 di-tert-amyl- 12 50 2. 3 100 phenyl)benzotriaz0le. 2- (2-hydroxy-3,, 5-di-tert-amyll M 100 0 72 phenyl)benzotriazole. 2-(2-hydroxy-3,5-di-tert-an1yl- 1:0 100 0 72 phenyDbenzotriazole. 2- (2-hydroxy-5-n-0ctylphenyl) 1 A 50 2. 1 100 benzotriazole. 2-(2'-hydroxy-5-n-octylphenyl) 1 100 O 100 benzotrlazole. 8 2-pho1ny l-5-palmitoyl amldobenzotri- 1:% 50 26 64 azo e. 9 2-(2-hydroxy-5-isooctyl-x-sulfo- 100 28 7? phenyl)bcnzotriazole, sodium salt.

1 Compound outside invention.

2 Fischer type.

A comparison of the results for Coating 1 and Coating 9 demonstrates that the unexpectedly high stability of my ultraviolet absorbing layers is not the result of the 2-(2- hydroxy-5'-isooctyl)benzotriazole structure but depends on the method of incorporation used in my invention.

Coatings 8 and 9 which fall outside my invention both show poor stability as evidenced by the serious losses in density in the ultraviolet region produced by exposure to xenon arc. Even more serious losses are shown by other absorbing compounds selected from outside the invention as is shown by Coatings 10 through 15. (See Table III below.)

Coatings 10 through were made for typical ultraviolet absorbers (identified in Table III) selected from outside the invention. Coatings 10 and 12 through 15 were from the composition described coated at mg/ft. of ultraviolet absorbing compounds except that in Coating 11 composition, n-butyl acetate was used as the organic solvent instead of tri-o-cresylphosphate.

The percent loss in transmission density produced by 100 hours exposure to xenon arc was determined as described previously. These data are given in Table III.

Coating 16 is identical with Coating l0. Coatings 17 and 18 were made according to the procedure described for Coating 9, using Fischer dispersions of ultraviolet absorbers having the same structure as the ultraviolet absorbing compound of Coating 10 but containing sulfonic acid water-solubilizing groups. The changes in transmis sion density produced by 64 hours exposure to xenon arc was determined as described previously and are shown in Table IV.

TABLE IV Percent Loss in Transmission Den- Ratio of sity of Ultraviolet Coating Ultraviolet Absorber Absorber Absorbing Coating to at x370 m Caused Solvent by 64 Hours Exposure to Xenon Are 16 5-benzylidene-3-eetyl-2 l:% 58. 5

phenyliminoA-thiazolidone. 17 5-(2-sulIobenzylidene)-3- Fiseher 3.0

cetylZ-phenyIiminQ-L thliizolidone, sodium sa l8 5-(2,4-disulfobenzylidene)- d0 2. 6

3-eetyl-2-phenylimino-4- thliazolidone, disodiurn so it.

These data clearly show the better stability of Fischertype analogues of a prior art ultraviolet absorber. Other absorbers, such as 3,3'-hexamethylenebis-Z-ethylimin0-5- benzylidene-4-thiazolidone, incorporated into gelatin layers by the solvent dispersion technique and compared with coatings containing the corresponding Fischer analogue,

the 5-(2-sulfobenzylidene) derivative, incorporated by the Fischer technique showed the better stability to light of the Fischer ultraviolet absorber coating over the ultraviolet absorber coating incorporated by solvent dispersion technique.

Tables II and III show that hours exposure to a xenon are produced only from O to 2.3 percent loss in density at A370 m, for my coatings compared to losses of from 59.2 to 83.0 percent for coatings made from solvent dispersions of ultraviolet absorbers outside the invention. Coating 8 (outside the invention) from a solvent dispersion of an ultraviolet absorber outside the invention showed a 26 percent loss in density and Coating 9 (outside the invention) which was made from a Fischer dispersion of ultraviolet absorbing compound showed a 28 percent loss in specular density after only 72 hours exposure to the xenon arc.

Table IV shows that 64 hours exposure to xenon are produced only 2.6 to 3 percent loss in density at A370 mg for Fischer coatings containing absorbers of the type known in the art while solvent dispersion coatings of the organic solvent-soluble analog are very unstable to light and showed a 58.5 percent loss in density.

It was unexpected that the compounds of my invention would be highly stable to light when incorporated by the solvent dispersion technique while the Fischer analogs incorporated by the Fischer process were unstable.

My invention is further illustrated in Example 2.

Example 2 The solvent dispersions for Coatings 19-22 of the following Table V were made for representative compounds of my invention, and a typical ultraviolet absorber of the prior art (Coating 22). One gram of ultraviolet absorber was dissolved in a mixture of 10 ml. of acetone and 9 ml. of methanol. A solution containing 20 ml. of phthalated gelatin, 300 ml. of water and 1 ml. of a 10 percent Alkanol B solution was added rapidly with agitation to the ultraviolet absorber solution to form finely dispersed particles of the ultraviolet absorber in which the ratio of absorber to gelatin was 1:2. Ten ml. of 1 percent citric acid was added to precipitate the gelatin containing the ultraviolet absorber, and after decanting and washing the coagulum, Water and saponin were added to make 40 ml. of solution which was heated to 40 C. and the pH adjusted to 5.6 to 5.8. The solution was coated on a clear support to 0.003 inch wet thickness and dried. The coatings contained 100 mg. of absorber/11.

The same procedure was used for the phenyliminothiazolidone derivative except that the ultraviolet absorber was dissolved in 200 ml. of acetone and a solution containing 20 ml. of phthalated gelatin, 400 ml. of water and 1 ml. of a 10 percent Alkanol B solution was added rapidly to the absorber solution.

Cary spectrophotometer traces as described in Example 1 were made for these solvent dispersion coatings and the percent loss in transmission density at a wavelength of 370 m was determined after xenon are fading. These values are tabulated in the following table.

The data in Table V clearly show the striking diiference in the long term stability of solvent dispersion coatings made according to my invention as compared to that of solvent dispersion coatings of a prior art ultraviolet absorber. My coatings showed substantially no change in density while the coating of the prior art absorber exhibited high loss in density after 100 hours xenon are fading.

The following examples further illustrate my invention.

Example 3 One gram of 2-(2-hydroxy-5'-iso-octylphenyl) benzotriazole, Compound 1, was dissolved by heating in 2 ml. of tri-o-cresyl phosphate to about 120 C. This solution was added to 20 ml. of ten percent gelatin and milled five times. The resulting dispersion was diluted with an equal volume of water and coated on both clear and opaque film support. These coatings had negligible absorption in the visual region and showed no change in absorption after 60 hours irradiation from a xenon arc.

A spectral absorption curve for this coating showed strong absorption of radiation in the region from 210 to 380 m with absorption peaks at 220, 296, and 335 III/1., respectively.

The following example illustrates the use of a low boiling solvent or auxiliary solvent along with the high boiling solvent in the preparation of a dispersion of the ultraviolet light absorbing compound.

Example 4 A multilayer element for color photography containing incorporated color forming couplers and an ultraviolet absorbing layer was prepared. On a paper support were coated in succession, layer 1 consisting of a blue-sensitive, silver bromide gelatin emulsion containing a yellow image-forming coupler (such as is described in Weiss- .berger US. Patent 2,298,443, issued October 13, 1942, McCrossen et al. US. Patent 2,875,057, issued February 24, 1959, etc.) dissolved in a high boiling solvent, such as di-n-butylphthalate, layer 2 a gelatin interlayer, layer 3 a green-sensitive, silver chlorobromide gelatin emulsion containing a pyrazolone (magenta-forming) coupler (such as is described in Porter et al. US. Patent 2,369,489, issued February 13, 1945, and others) dissolved in tri-ocresyl phosphate, layer 4 an ultraviolet absorbing layer, layer 5 a red-sensitized, silver chlorobromide gelatin emulsion containing a cyan-forming phenolic coupler (such as is described in Salminen et al. US. Patent 2,423,730, issued July 8, 1947, and others) dissolved in a suitable high boiling solvent such as di-n-butylphthalate, and layer 6 protective gelatin overcoat.

The coupler dispersions were made according to the dispersion techniques described previously.

Two samples of these coatings were made, sample A had as layer 4 an ultraviolet absorbing layer made as Coating 1 of Table II but containing 100 mg. of ultraviolet absorber per ft. of coating, while sample B had as layer 4, coating 10 of Table III but containing 100 mg. of ultraviolet absorber per ft. of coating.

Sample Coatings A and B were given identical exposure to light through a silver step wedge so that the coating under the densest area of the step wedge received no exposure. The samples were given identical processing, comprising development in a developer having the composition:

Grams 4-amino-N,N-diethyl-3-methylaniline hydrochloride-.. 2 Sodium carbonate, monohydrate 20 Sodium sulfite, desiccated 2 Potassium bromide 2 Water to make 1 liter.

treatment in a conventional acid stop bath, washing, bleaching in a conventional potassium ferricyanide-potassium bromide bleach, washing, fixing in a conventional TABLE V Percent Reflectance to Light of Sample 400 m 420 m 440 m 500 my A 5s 63 e7 74' B 27 49 64 73 My ultraviolet absorbing layer is coated from a composition comprising a solvent dispersion of a compound of Formula I made by dissolving the compound in an organic solvent and dispersing this solution in an aqueous solution of a hydrophilic colloid or binder.

Binders that are particularly advantageous to use in clude gelatin, albumin, etc., cellulose derivatives, polyvinyl compounds, etc. The polymeric binders include polyvinyl alcohol or a hydrolyzed polyvinyl acetate as described in Lowe US. Patent 2,286,215, issued June 16, 1942; a far hydrolyzed cellulose ester such as cellulose acetate hydrolyzed to an acetyl content of 19-26 percent as described in U.S. Patent 2,327,808 of Lowe and Clark, issued August 24, 1943; a water-soluble ethanolamine cellulose acetate as described in Yutzy US. Patent 2,322,- 085, issued June 15, 1943; a polyacrylamide having a. combined acrylamide content of 30-60 percent and a specific viscosity of 025-15 on an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe, Minsk and Kenyon US. Patent 2,541,- 474, issued February 13, 1951; zein as described in Lowe US. Patent 2,563,791, issued August 7, 1951; a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh and Smith US. Patent 2,768,154, issued October 23, 1956; or containing cyanoacetyl groups such as the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smith and Priest US. Patent 2,808,331, issued October 1, 1957; or a polymeric material which results from polymerizing a protein or a saturated acylated protein with a monomer having a vinyl group as described in U.S. Patent 2,852,382, of Illingsvvorth, Dann and Gates, issued September 16, 1958.

The dispersion of an absorbing compound of Formula I in the binder material is coated over the light-sensitive layer of the photographic element. Where the photographic element is a material intended for use in color photography, the ultraviolet filter layer need not be an outer layer, but can be used as an interlayer, i.e., under the layer or layers not needing the protection and over the layer or layers needing protection. For example, in a multilayer material comprising three dilferentially sensitized layers, the red-sensitive layer being adjacent to the support, the green-sensitive layer being superimposed on the red-sensitive layer and the blue-sensitive layer being outermost with respect to the other light-sensitive layers, the ultraviolet filter layer can be placed between the blueand green-sensitive layers or between the greenand red-sensitive layers. Similarly, in another photographic element in which the layers are reversed, that is, the blue-sensitive layer is coated over the support, and the greenand red-sensitive layers are superposed over the blue-sensitive layer in that order, the ultraviolet filter layer can be over all three layers or between any two of the layers. Alternatively, the ultraviolet absorbing composition can be incorporated directly in the light-sensitive emulsion instead of, or in addition, being present in 1 1 another layer. The amount of the ultraviolet absorbing material used can be varied, depending upon the effect desired and the use that will be made of the material.

The invention is still further illustrated by the accompanying drawing which shows a greatly enlarged crosssectional view of a multilayer element containing my ultraviolet absorbing layer.

The drawing shows paper support 10, coated with 11 a blue-sensitive silver halide emulsion layer containing a yellow-dye-forming coupler, that is coated over by layer 12 a green-sensitive silver halide emulsion containing a magenta-dye-forming coupler, that is coated with gelatin =layer 13 containing a dispersion of 2-(2-hydrox y-5-isooctylphenyl)benzotriazole dissolved in tri-o-cresyl phosphate (at a ratio of 12 /2), that is coated with layer 14 a red-sensitive silver halide emulsion containing a cyandye-forming coupler, and finally coated with gelatin overcoat 15.

My ultraviolet absorbing compositions are coated over a wide range of concentrations; usually they are coated in the range of from 20 to 300 mg. of ultraviolet absorbing compound per ft. photographic element. A preferred range is from 75 to 160 mg./ft. The optimum coating concentrations will depend upon the particular photographic element to be protected and the amount of protection desired. The optimum coating concentrations for a given photographic element can be determined by methods well known in the art.

Any photographic element may be advantageously protected according to my invention. These photographic elements may have as their support any of the conventional support materials, such as film supports, e.g., cellulose acetate, etc., opaque supports, such as white pigmented film, paper, etc.

The invention is still further illustrated by the following description of the syntheses of representative compounds of Formula I.

Compound 1 was prepared as follows. Seven grams (0.1 mole) of sodium nitrite was added slowly to 44 ml. of concentrated sulfuric acid. The temperature rose to 70 C. When the mixture became clear, it was cooled to 20, and 13.8 g. (0.1 mole) of o-nitroaniline was added With vigorous stirring. The ensuing syrupy reaction mixture was added to 240 g. of ice.

The above diazonium solution was added with stirring to a solution prepared by dissolving 20.8 g. (0.1 mole) of 4-isooctylphenol in 100 ml. of methanol. This solution was then added to a solution of 200 g. of sodium acetate in 200 ml. of water. The red solid which precipitated was recrystallized from methanol giving 17.5 g. of red needles, M.P. 96-97 C. The yield was 49.3 percent of the theoretical.

Seven and one-tenth grams (0.02 mole) of the 2-nitrophenylazo-2'-hydroxy-5'-isooctylbenzene was suspended in 150 ml. of ethanol and heated to refluxing temperature, then a solution of 25 g. of sodium hydroxide in 150 ml. of water and 8 g. of zinc dust was added. Refluxing was continued for one hour. The yellow solution was filtered from a small amount of unreacted zinc and neutralized to litmus with hydrochloric acid. The yellowish precipitate was recrystallized from methanol giving 4.7 g. (73.4 percent) of yellow needles, M.P. 98-99.

Compound 2 was prepared by the same method as Compound 1 but using 4-n-octylphenol in place of 4-isooctylphenol. Compound 2 had a M.P. of 8687 C.

Compound 3 was prepared by the method used to make Compound 1 but using 2,4-di-tert-amylphenol in place of the 4-octylphenol. Compound 4 had a M.P. of 77-78 C.

Compound 4 was prepared by the method used to make Compound 1 but using 4-dodecylphenol in place of the 4-octylphenol. The product had a M.P. of 7277 C.

Compound 5 was prepared similarly to Compound 1 but substituting 4-hexadecylphenol for the 4-octylphenol. The product had a M.P. of 6970 C.

Compound 6 may be prepared similarly to Compound 1 but substituting Z-tert-amyl-4-benzylphenol for the 4- octylphenol.

Compound 7 may be prepared similarly to Compound 1 but substituting 2-tert-amyl-4-phenylphenol for the 4- octylphenol.

Compound 8 may be prepared similarly to Compound 1 but using 4-a-mino-5-nitrotoluene in place of o-nitroaniline.

Compound 9 may be prepared similarly to Compound 1 but using 2-nitro-4-isooctylan'iline in place of o-nitroaniline. The 2-nitro-4-isooctylaniline is prepared by nitrating issoctylbenzene, isolating the 4-nitroisooctylbenzene, reduction of this to the amino compound, acetylation of the amino group, nitration to make the 2-nitro derivative followed by hydrolysis.

Compound 10 may be prepared similarly to Compound 1 but using 2-nitro-4-carbobutoxy aniline in place of 0- nitroaniline and 2-n-butyl-4-tert-arnylphenol in place of the 4-octylphenol.

Compound 11 may be prepared similarly to Compound 1 but using 2-nitro-4-chloroaniline in place of o-nitroaniline and 2-n-amyl-4-phenylphenol in place of the 4- octylphenol.

Compound 12 may be prepared similarly to Compound 1 but using 2-nitro-4-methoxyaniline in place of o-nitroaniline and 2,4-di-tert-amylphenol in place of 4-octylphenol.

Compound 13 may be prepared similarly to Compound 1 but using 2,4-dinitroaniline in place of o-nitroaniline and 2-n-octyl-4-methoxyphenol in place of 4-octylphenol.

Compound 14 may be prepared similarly to Compound 1 but using 4-chloro-2-nitroaniline in place of o-nitroaniline and 2-tert-butyl-4-cyclohexylphenol in place of 4- octylphenol.

Compound 15 may be prepared similarly to Compound 1 but using 2-nitro-4-methylaniline instead of o-nitroaniline and 2-chloro-4-octylphenol in place of 4-octylphenol.

Compound 16 may be prepared similarly to Compound 1 but using 2-nitro-4-phenylaniline instead of o-nitroaniline and 2,4-di-tert-amylphenol instead of 4-octylphenol.

Compound 17 may be prepared similarly to Compound 1 but using 2-nitro-4-methylaniline instead of o-nitroaniline and 2-tert-amyl-4-phenoxyphenol instead of 4- octylphenol.

An alternative synthesis that can be used involves the reaction of a phenylhydrazine with an aromatic hydrocarbon having nitro and chlorine substituents on neighboring carbon atoms. The yields produced, however, are low and the availability of appropriate phenylhydrazines limits the applicability of this synthesis.

The ultraviolet absorbing compounds of Formula I are characterized by their nonditfusi'bility in coated layers, good stability in the incorporating solvents, and their good ultraviolet absorption. Ultraviolet absorbing layers containing compounds of Formula I incorporated according to the preferred methods of my invention have unexpectedly excellent stability upo'n prolonged exposure to ultraviolet radiation which makes them ideally suited for protecting photographic elements, particularly dye images in color materials.

The amount of solvent to be retained in the final coating made according to my invention can be adjusted according to the requirements of the product and by selecting solvents or a mixture of solvents of appropriate volatility and/or water solubility.

Some ultraviolet absorbing layers made in the same manner using prior art absorbers as described in Example 1 showed from 59 to 83 percent loss in specular density at an arbitrarily selected near-visible wave length of 370 m as a result of hours exposure to a xenon arc while my layers showed only from 0 to 2.3 percent loss under the same conditions. The high stability of my ultraviolet absorbing layers is even more surprising since ultraviolet absorbing layers made by the incorporation of water-solubilized derivatives, e.g., 2 (2-hydroxy-5'-isooctyl-X-sulfophenyl)benzotriazole, sodium salt, of the same ultraviolet absorbing compounds directly in a colloidal binder have shown poor stability as indicated by a serious loss in specular density at the A 370 m after only 72 hours exposure to a xenon arc. Also, compounds analogous to Formula I, but without the 2-hydroxy substituent on the 2-phenyl ring, e.g., as used in Coating 8 of Example 1-, showed a seriou loss in density after only 64 hours exposure to a xenon arc.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within thespirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. An ultraviolet absorbing dispersion comprising a hydrophilic colloid binder material and a hydrophobic compound selected from those having the formula:

wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contains at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

2. An ultraviolet absorbing dispersion comprising a hydrophilic colloid binder material, a solvent and a hydrophobic compound selected from those having the formula:

wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contain at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

3. An ultraviolet absorbing dispersion of claim 2 in which said solvent is a high boiling water-immiscible organic solvent.

4. An ultraviolet absorbing dispersion of claim 2 in which said solvent is a water miscible organic solvent.

5. An ultraviolet absorbing dispersion of claim 2 in which said solvent is a low boiling organic solvent.

6. An ultraviolet absorbing layer for photographic elements coated from a dispersion of claim 2.

7. A photographic element protected against ultraviolet radiation by a protective amount of a dispersion of claim 1.

8. A photographic element protected against ultraviolet radiation by a protective layer coated from a dispersion of claim 2.

9. A photographic element comprising a support, at least one hydrophilic colloid photographic silver halide emulsion layer, and incorporated in one of the hydrophilic colloid layers of said photographic element a hydrophobic compound selected from those represented by the following formula:

wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contains at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

10. A photographic element comprising a support, at least one photographic silver halide emulsion layer, superposed on said support, and an outer gelatin layer containing a hydrophobic compound selected from those represented by the formula:

wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contain at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

11. A finished photographic element comprising a support having thereon a plurality of developed and fixed photographic emulsion layers containing developed-dye images, at least one of said dye images being subject to fading by the action of ultraviolet radiation, said emulsion layer containing a developed-dye image subject to fading lying between said support and a gelatin layer containing an ultraviolet absorbing hydrophobic compound selected from those represented by the following formula:

wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contain at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

12. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a hydrophilic colloid layer containing a dispersion of 2-(2'- hydroxy-S -iso-octylphenyl benzotriazole.

13. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a hydrophilic colloid layer containing a dispersion of 2-(2- hydroxy-3 ',5'-di-tert-amlyphenyl benzotriazole.

14. A photographic element comprising a su port, a photographic gelatino-silver halide emulsion layer, and a 15 hydrophilic colloid layer containing a dispersion of 2-(2- hydroxy--dodecylphenyl)benzotriazole.

15. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a hydrophilic colloid layer containing a dispersion of 2-(2'- hydroxy-S'-hexadecylphenyl benzotriazole.

16. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a hydrophilic colloid layer containing a dispersion of 5- methyl 2 (2 hydroXy 5' iso octylphenyl) benzotriazole.

17. A method of preventing image degradation in a finished photographic element comprising a plurality of developed and fixed photographic emulsion layers containing developed-dye images, at least one of said dye images being subject to fading by the action of ultraviolet radiation, said emulsion layer containing a developed-dye image subject to fading lying between a support and a gelatin outer layer, which comprises applying to said photographic element a hydrophilic colloidal binder material containing a solvent dispersion of a hydrophobic compound selected from those having the formula:

18. An aqueous gelatin coating composition comprising a dispersion of water, gelatin and an ultraviolet absorbing hydrophobic compound selected from those having the formula:

I R 1 R wherein R, R and R each represents a member selected from the class consisting of a hydrogen atom, a halogen atom, a nitro group, an alkyl group having from 1 to 18 carbon atoms, an alkoxy group having from 1 to 18 carbon atoms, an aryl group, and an aryloxy group such that at least one of the groups R, R and R contains at least 5 carbon atoms and the total number of carbon atoms represented in R +R is at least 8.

19. An aqueous gelatin coating composition of claim 18 containing an organic solvent for said ultraviolet absorbing compound.

References Cited by the Examiner UNITED STATES PATENTS 2,647,057 7/1 953 Seary et al. 88 2,940,815 6/1960 Tara 835 2,947,628 8/1960 Fierke et al 9684 X 3,004,896 10/1961 Heller et al 252--300 3,018,269 1/1962 Bruno 252300 3,055,896 9/1962 Boyle et al. 252300 OTHER REFERENCES Gysling et al., Chem. Abstracts, vol. 55, No. 12, June 12, 1961, col. 11906f, abstract of Kunststoffe, 51, 13l7 (1961).

NORMAN G. TORCHIN, Primary Examiner.

LOUISE P. QUAST, Examiner.

A. L. LIBERMAN, J. H. RAUBITSCHEK,

Assistant Examiners.

po-wso UNITED STATES PATENT OFFICE 56g CERTIFICATE OF CORRECTION Patent No. 3 2 53 :9 Dated y 3 s 1 9 Inventor(s) George W. Sawdey It is certified that error appears in the above-identified patent and that said Letters Patent are hereby correc'zted as shown below:

73 011mm 11 line 27, that portion of the formula reading R l should N J read R N/ Column 1b., line 53, that portion of the formula reading li should R Signed and sealed this 17th day of February 1970.

(SEAL) Attest 2 EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

9. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT, AT LEAST ONE HYDROPHILIC COLLOID PHOTOGRAPHIC SILVER HALIDE EMULSION LAYER, AND INCORPORATED IN ONE OF THE HYDROPHILIC COLLOID LAYERS OF SAID PHOTOGRAPHIC ELEMENT A HYDROPHOBIC COMPOUND SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING FORMULA: 